1. Field of the Invention
This invention relates to an extraction preventing device for a connector and more particularly relates to an extraction preventing device that is provided in an electrical junction box and serves to restrain a connector fitted in a connector containing member on the electrical junction box from being readily extracted to prevent a car theft or the like.
2. Description of the Related Art
A connector is fitted in a connector containing member on an electrical junction box to be installed in a motor vehicle. A piece being latched is flexible from a front end to a rear end and protrudes from a housing outer surface of the connector. The piece being latched is provided with a projection being latched that is locked on the connector containing member. An example of such connector has been disclosed in JP 2006-228461 A.
As shown in FIGS. 4A and 4B, a connector 1 having an above structure is fitted in a connector containing member 2. The connector 1 is provided on a housing outer surface 1a with a piece being latched 1b that protrudes from the housing outer surface 1a and with a projection being latched 1c that protrudes from the piece being latched 1b. The connector containing member is provided on an inner surface with a connector latching projection 2a to be locked on the projection being latched 1c. 
In order to fit the connector 1 into the connector containing member 2, firstly the connector 1 is inserted into the connector containing member 2 while the piece being latched 1b is deflected toward the housing outer surface 1a. Then, the projection being latched 1c slides over the connector latching projection 2a. When the piece being latched 1b returns to the original position on account of its elasticity, the projection being latched 1c is locked on the connector latching projection 2a. The piece being latched 1b of the connector 1 is provided on a rear end with a lock release operating portion 1d for releasing a locking state between the connector latching projection 2a and the projection being latched 1c. When a person pushes the lock release operating portion 1d by his or her finger to release the locking state, the connector can be readily removed from the connector containing member 2.
On the other hand, a serious problem of a car theft has been occurred recently in Japan and the foreign countries. To overcome the above problem, an anti-theft system such as an immobilizer has gone into actual use. For example, the immobilizer checks an ID code of an electronic communication chip (transponder) embedded in a key for a motor vehicle against an ID code registered before hand in an electronic control unit (ECU). If both codes do not coincide with each other, an engine in the motor vehicle is not started. This system is superior in point of an anti-theft effect.
However, if a unit related to an immobilizer including an electrical junction box is exchanged for an alternative unit at a time, an engine in a motor vehicle will be started without checking the ID codes, thereby enabling the motor vehicle to move as a theft car. Accordingly, it is a very important matter to make it difficult to extract a connector fitted in a connector containing member in a given electrical junction box, and to prevent the unit related to the immobilizer from being exchanged for an alternative unit.
However, since the locking state between the connector latching projection 2a and the projection being latched 1c can be readily released in the above fitting structure of the connector 1, there is a problem that the connector 1 is likely to be extracted from the connector containing member 2.